• Thomas R. Hay, Ph.D., P.E

Phased Array Testing to Bridge Welding Code


Phased array ultrasonic testing (PAUT) is presented in detail in the American Welding Society (AWS) D1.5 Bridge Welding Code (BWC). The code book presents the usual sections including Scope, Definitions, Personnel Requirements, Equipment, etc. In this article, the focus is on phased array ultrasonic testing (PAUT) accept/reject criteria and how to apply them real data from a structural steel welds.

AWS Bridge Welding Code PAUT Acceptance Criteria

The BWC defines four different discontinuity classes: A, B, C, and D. Discontinuity Class A is the most severe, intermediate Classes B and C, and least severe Class D. They are categorized by the ultrasonic wave reflected amplitude of the weld discontinuity detected by phased array. The four different amplitude threshold levels are Automatic Reject Level (ARL), Standard Sensitivity Level (SSL), and Disregard Level (DRL). The SSL is set using the 0.060” diameter side drilled hole (SDH) on the IIW calibration block to 50% full-screen height (%FSH). The ARL is set 5 dB above the SSL and which is equivalent to 89 %FSH. Lastly, the DRL is set to 25 % FSH. The phased array discontinuity classes are defined in the AWS D1.5 Discontinuity Classification table shown below.